In Situ TEM Reveals Direct One-Step Reduction of van der Waals Crystal MoO 3 to Mo

作者：Wei Tu, Fan Zhang, Xiankun Song, Jin Lu, An Bai, Zhen Zeng, T. D. Xu, Xianhu Sun, Yao Yang, Jianyu Huang · 发表于：Nano Letters · 年份：2025 · DOI：10.1021/acs.nanolett.5c03929 · 被引用次数：7 · 研究领域：Transition Metal Oxide Nanomaterials、ZnO doping and properties、Semiconductor materials and devices

Molybdenum oxides (MOs) exhibit rich polymorphism and tunable properties, yet their phase transformation pathways are poorly understood. Here, we employ in situ environmental transmission electron microscopy (TEM) to reveal a direct reduction of MoO 3 to metallic Mo, bypassing known intermediate phases such as MoO 2 and Mo 4 O 11 . Surface nucleation begins at approximately 800 °C and is completed at 900 °C. Molecular dynamics (MD) and density functional theory (DFT) calculations attribute this unexpected transformation to the van der Waals (vdW) layered structure of MoO 3, which lowers both the oxygen binding energy and the Gibbs free energy (ΔG) for oxygen desorption under high-vacuum and high-temperature conditions. Preferential oxygen removal from the weakly bonded vdW layers facilitates a rapid reduction to the metallic phase. These findings uncover a nonclassical reduction mechanism and provide a pathway for the rational design of MOs with controllable phases and properties.